Qualifications of Candle Filters for Combined Cycle Combustion Applications

The direct firing of coal produces particulate matter that has to be removed for environmental and process reasons. In order to increase the current advanced coal combustion processes, under the U.S. Department of Energy's auspices, Siemens Westinghouse Power Corporation (SWPC) has developed ceramic candle filters that can operate at high temperatures. The Coal Research Center of Southern Illinois University (SIUC), in collaboration with SWPC, developed a program for long-term filter testing at the SIUC Steam Plant followed by experiments using a single-filter reactor unit. The objectives of this program funded by the U.S. Department of Energy were to identify and demonstrate the stability of porous candle filter elements for use in high temperature atmospheric fluidized-bed combustion (AFBC) process applications. These verifications were accomplished through extended time slipstream testing of a candle filter array under AFBC conditions using SIUC's existing AFBC boiler. Temperature, mass flow rate, and differential pressure across the filter array were monitored for a duration of 45 days. After test exposure at SIUC, the filter elements were characterized using Scanning Electron Microscopy and BET surface area analyses. In addition, a single-filter reactor was built and utilized to study long term filter operation, the permeability exhibited by a filter element before and after the slipstream test, and the thermal shock resilience of a used filter by observing differential pressure changes upon rapid heating and cooling of the filter. The data acquired during the slipstream test and the post-test evaluations demonstrated the suitability of filter elements in advanced power generation applications

Electrodeposition of MoS2 for Charge Storage in Electrochemical Supercapacitors

Mo sulfide thin films were cathodically electrodeposited onto glassy carbon electrodes (GCE) from aqueous electrolytes containing 10 mM (NH4)2MoS4 and 0.2 M KCl. Film adhesion was adequate only for electrodes pretreated by potential cycling in 1.0 M HNO3 and 0.1 M NaF to enhance the surface roughness and partially oxidize the GCE. Previous studies report direct cathodic electrodeposition of MoS2, but energy dispersive x-ray spectroscopy and x-ray diffraction suggest that the as-deposited film is closer in stoichiometry to MoS3, which can be converted to MoS2 by annealing in Ar at 600°C for one hour. The charge storage capability of electrodeposited Mo sulfide films is studied here for the first time in 1.0 M Na2SO4 over the thickness range 50 nm to 5 µm, and before and after high temperature annealing. The highest capacitance is obtained for 50 nm thick MoS2 films is 330 F/g measured by galvanostatic charge discharge at 0.75 A/g, and 360 F/g measured by cyclic voltammetry at 10 mV/sec. The capacitance per unit mass decreases with increasing film thickness due to reduced electrochemical accessibility. MoS2 film formed by high temperature annealing in Ar have a charge storage capability about 40x higher than the as-deposited Mo sulfide films

FUEL-FLEXIBLE GASIFICATION-COMBUSTION TECHNOLOGY FOR PRODUCTION OF H2 AND SEQUESTRATION-READY CO2

It is expected that in the 21st century the Nation will continue to rely on fossil fuels for electricity, transportation, and chemicals. It will be necessary to improve both the process efficiency and environmental impact performance of fossil fuel utilization. GE Energy and Environmental Research Corporation (GE EER) has developed an innovative fuel-flexible Unmixed Fuel Processor (UFP) technology to produce H{sub 2}, power, and sequestration-ready CO{sub 2} from coal and other solid fuels. The UFP module offers the potential for reduced cost, increased process efficiency relative to conventional gasification and combustion systems, and near-zero pollutant emissions including NO{sub x}. GE EER was awarded a Vision 21 program from U.S. DOE NETL to develop the UFP technology. Work on this Phase I program started on October 1, 2000. The project team includes GE EER, California Energy Commission, Southern Illinois University at Carbondale, and T. R. Miles, Technical Consultants, Inc. In the UFP technology, coal/opportunity fuels and air are simultaneously converted into separate streams of (1) pure hydrogen that can be utilized in fuel cells, (2) sequestration-ready CO{sub 2}, and (3) high temperature/pressure oxygen-depleted air to produce electricity in a gas turbine. The process produces near-zero emissions and, based on process modeling work, has an estimated process efficiency of 68%, based on electrical and H{sub 2} energy outputs relative to the higher heating value of coal, and an estimated equivalent electrical efficiency of 60%. The Phase I R&D program will determine the operating conditions that maximize separation of CO{sub 2} and pollutants from the vent gas, while simultaneously maximizing coal conversion efficiency and hydrogen production. The program integrates lab-, bench- and pilot-scale studies to demonstrate the UFP technology. This is the ninth quarterly technical progress report for the Vision 21 UFP program supported by U.S. DOE NETL (Contract No. DE-FC26-00FT40974). This report summarizes program accomplishments for the period starting October 1, 2002 and ending December 31, 2002. The report includes an introduction summarizing the UFP technology, main program tasks, and program objectives; it also provides a summary of program activities and accomplishments covering progress in tasks including lab- and bench-scale experimental testing, pilot-scale design and assembly, and program management

Fuel-Flexible Gasification-Combustion Technology for Production of H2 and Sequestration-Ready CO2

GE Global Research is developing an innovative energy technology for coal gasification with high efficiency and near-zero pollution. This Unmixed Fuel Processor (UFP) technology simultaneously converts coal, steam and air into three separate streams of hydrogen-rich gas, sequestration-ready CO{sub 2}, and high-temperature, high-pressure vitiated air to produce electricity in gas turbines. This is the draft final report for the first stage of the DOE-funded Vision 21 program. The UFP technology development program encompassed lab-, bench- and pilot-scale studies to demonstrate the UFP concept. Modeling and economic assessments were also key parts of this program. The chemical and mechanical feasibility were established via lab and bench-scale testing, and a pilot plant was designed, constructed and operated, demonstrating the major UFP features. Experimental and preliminary modeling results showed that 80% H{sub 2} purity could be achieved, and that a UFP-based energy plant is projected to meet DOE efficiency targets. Future work will include additional pilot plant testing to optimize performance and reduce environmental, operability and combined cycle integration risks. Results obtained to date have confirmed that this technology has the potential to economically meet future efficiency and environmental performance goals

Qualifications of Candle Filters for Combined Cycle Combustion Applications

The direct firing of coal produces particulate matter that has to be removed for environmental and process reasons. In order to increase the current advanced coal combustion processes, under the U.S. Department of Energy's auspices, Siemens Westinghouse Power Corporation (SWPC) has developed ceramic candle filters that can operate at high temperatures. The Coal Research Center of Southern Illinois University (SIUC), in collaboration with SWPC, developed a program for long-term filter testing at the SIUC Steam Plant followed by experiments using a single-filter reactor unit. The objectives of this program funded by the U.S. Department of Energy were to identify and demonstrate the stability of porous candle filter elements for use in high temperature atmospheric fluidized-bed combustion (AFBC) process applications. These verifications were accomplished through extended time slipstream testing of a candle filter array under AFBC conditions using SIUC's existing AFBC boiler. Temperature, mass flow rate, and differential pressure across the filter array were monitored for a duration of 45 days. After test exposure at SIUC, the filter elements were characterized using Scanning Electron Microscopy and BET surface area analyses. In addition, a single-filter reactor was built and utilized to study long term filter operation, the permeability exhibited by a filter element before and after the slipstream test, and the thermal shock resilience of a used filter by observing differential pressure changes upon rapid heating and cooling of the filter. The data acquired during the slipstream test and the post-test evaluations demonstrated the suitability of filter elements in advanced power generation applications

The conversion of syngas to liquid fuels in a dual-bed single reactor process

V článku uvedeno Juchelová.The effects of HZSM-5 temperature and weight hourly space velocity (WHSV) on conversion of syngas to liquid fuels were investigated in a single reactor process. The temperature of FT catalyst was constant (463 K), whereas the temperature of HZSM-5 varied (523, 573, 623 K). The value of WHSV ranged between 16 and 24 h−1. HZSM-5 addition suppressed the formation of CH4 and remarkably enhanced the formation of iso-C5-C12 paraffins. An increase of HZSM-5 temperature resulted in an enhancement of gaseous hydrocarbons, C18+ paraffins, and olefins. The optimal HZSM-5 temperature and WHSV were identified as 523 K and 16 h−1, respectively.Web of Science32222729272

Gaseous components from pyrolysis-Characteristics, production and potential for energy utilization

This article is focused on a complex evaluation of the process gas produced within an experimental pilot-scale system which thermally processes input materials by a form of pyrolysis. The Pyromatic system is a unique device. Its originality consists in its ability to continually process secondary organic raw materials. Within the Czech Republic, it does not have any parallel to its power output (it can process up to 150 kg of input material per hour) and its design. The presented results and conclusions show the product yield and characteristics of the gaseous product from this system with regard to a selected input material and process conditions. Three kinds of material were chosen for pyrolysis—biomass, brown coal, and rubber. Attention was especially focused on the gas quality related to energy and its combustion characteristics. The aim was to introduce all important characteristics (gross calorific value, flammability limit, propagation rate, Wobbe index, combustion potential, etc.) that adumbrate the possibilities and potential of this gas utilization in the power industry.Web of Science1068

Conversion of syngas to LPG and aromatics over commercial Fischer-Tropsch Catalyst and HZSM-5 in a dual bed reactor

The commercial Co-based Fischer-Tropsch catalyst and HZSM-5 were tested in a single reactor process. FT catalyst was evaluated at 463 K, whereas HZSM-5 was evaluated at various temperatures (523, 573, and 623 K). The effect of syngas flow rate, HZSM-5 temperature and loading on liquefied petroleum gas (LPG) and aromatics selectivities were investigated. HZSM-5 addition suppressed the formation of CO2 and CH4, and remarkably enhanced the simultaneous formation of LPG and aromatics. The optimal operating conditions were identified as: THZM-5 = 623 K, HZSM-5 loading = 2.5 g, and GHSV = 4.8 Lsyngas/(gcat h).Web of Science32202505249

Investigation of Co-Gasification Reactivity of Torrefied Jatropha Seed Cake with Illinois #6 Coal Char

Coal and torrefied biomass co-gasification is one of the potential solutions to the reduction of greenhouse gas emissions. For this study, Jatropha seed cake was torrefied at a temperature range of 200 to 300 °C under a nitrogen atmosphere. The torrefied material was then co-pyrolyzed and isothermally co-gasified at 900 °C with two Illinois (IL) #6 coal chars in a fixed-bed reactor connected to an on-line gas chromatography analyzer. Carbon dioxide and carbon monoxide were the primary gas products from the torrefaction process. Kinetic models, such as the shrinking core model, the homogenous model, and the catalysis-controlled model, were used to analyze the gasification mechanism. The results showed that the shrinking core and homogenous models provided the best fits for the gasification reaction data. Jatropha seed cake torrefied at 260 and 280 °C exhibited the best reaction activity with the IL #6 coal chars. The reactivities of coal char with torrefied biomass obtained at 200 and 300 °C were lower in comparison with the others

Conditions for energy generation as an alternative approach to compost utilization

Very strict limits constrain the current possibilities for compost utilization in agriculture and for land reclamation, thus creating a need for other compost utilization practices. A favourable alternative can be compost utilization as a renewable heat source - alternative fuel. The changes of the basic physical-chemical parameters during the composting process are evaluated. During the composting process, energy losses of 920 kJ/kg occur, caused by carbohydrate decomposition (loss of 12.64% TOC). The net calorific value for mature compost was 11.169 kJ/kg dry matter. The grain size of compost below 0.045 mm has the highest ash content. The energetic utilization of compost depended on moisture, which can be influenced by paper addition or by prolonging the time of maturation to six months